Orbital Fracture

A wide range of ocular trauma can occur concomitant with orbital fractures. The ocular Sequelae of mid-facial fractures are usually considered to be edema and ecchymosis of the soft tissues, subconjunctival hemorrhage, diplopia, iritis, retinal edema, Ptosis, enophthalmos, ocular muscle paresis, mechanical restriction of ocular movement and nasolacrimal disturbances. More severe injuries such as optic nerve trauma and retinal detachments have also been reported. Made known rates of intraocular injury range from 1% to nearly 70%

The relationship, if any, between the purity of orbital fractures and their secondary ocular problems has not been elucidated to date.

Intraocular injuries occur in a wide pattern when orbital bones are fractured. While several studies have reminded the community of the importance of the ophthalmic examination in patients who sustain orbital fractures, to date, there have been only a handful of studies which focus on the incidence of intraocular injuries in patients with fracturesOcular Injury

Of these, there is no agreement as to the incidence of injury. It is likely that the specialty of the physician conducting the research might account for the inconsistencies. In contrast, since our hospital protocol requires that all orbital fractures receive an ophthalmic examination, we believe that our results are unbiased; the true incidence of intraocular injury is approximately 17%.

The rates of injury were also compared between pure orbital floor fractures (only floor) and impure (floor and rim). Of patients who sustained a pure orbital floor fracture, intraocular injuries occurred in 5.6%, compared with only 2% that sustained an impure fracture. Intraocular injuries are more common in patients who sustained PURE orbital fractures than in patients with rim involvement (IMPURE) (p=0.05). This difference suggests that the mechanism of injury might not be the same in each; it might not simply be solely direct force transmitted to the rim as the buckling theory suggests.Intraocular Injuries

Recall that the "retropulsion" theory refers to a fracture of the orbital floor caused by sudden increase in intraorbital pressure (BLOW-OUT) which occurs when an object with sufficient force hits the aperture of the orbit and forces the soft orbital contents posteriorly. Such trauma is created by objects larger than the horizontal diameter of the orbit, such as from a fist or a ball. On the other hand, the "buckling theory" proposes that the force transmitted through the rigid orbital rim directly to the thin floor , causes the floor to fracture, usually leaving the rim intact.

If we accept that impure fractures are the lead to of direct trauma to the orbital rim and resultant buckling of the floor, then we would expect similar rates of intraocular injury between pure and impure orbital fractures. This would be the case IF the buckling theory is the correct theory for pure fractures, since both are created by the same direct force to the rim.

However, we find that the incidence of injury is significantly higher in the pure fracture group suggesting that a different mechanism is at play. It is more reasonable to envision that the acute rise in orbital pressure would lead not only to the floor fracturing, but also to a greater incidence of intraocular injury as the globe retropulses. One could argue, however, that in the case of the impure fracture, the rate of injury is lower because the force is blunted by the rim. Nevertheless, we believe that these data suggest that the retropulsion theory might be the more likely explanation for orbital fractures; one theory (retropulsion) can explain variations of ocular findings in both pure and impure fractures

Buckling:

It states that the orbital rim buckles and transmits forces to the orbital walls, resulting in an orbital floor fracture.

Retropulsion:

The "retropulsion" theory, advanced by Smith and Regan, refers to a fracture of the orbital floor caused by sudden increase in intra-orbital pressure; a fracture might lead to from the hydraulic forces generated in the closed orbital cavity.

Blows from a fist, for instance, or objects larger than the horizontal diameter of the orbit, are the most frequent cause of this type of fracture

Globe to Wall:

Consequences of trauma

Double Vision

Results from an inability of both eyes to move equally

The "buckling" theory maintains that an anterior force is transmitted back into the orbit.

See pre-operative and post-operative photos below illustrating down gaze limitation of the right eye.